Damper



Feb. 8, 1944. J, L, HARRIS 2,341,038

DAMPER Filed Mann 29, 1940 Fig. 1

menton? v Tohru L. Harris Patented Feb. 8, 1944 UNITED STATES PATENT OFFICE DANIPER John L. Harris, Minneapolis, Minn., assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application March 29, 1940, Serial No. 326,687

Claims.

This invention relates to dampers of thevcooperating louver type and particularly to the type of such damper in which adjacent louvers rotate in relatively opposite angular directions during any particular operation whether opening or i' closing.

Such dampers are now well known in the art and have the advantage over the conventional damper in which adjacent blades remain parallel oi providing a smoother flow of air through the damper at the smaller openings. In order to provide a tight shut-off in closed position it is desirable that adjacent damper blades overlap and the problem is introduced of opening the louvers in such a way that there will be no interference between adjacent louvers as they are moved from closed position. To accomplish this the louver which overlaps must move faster initially than the overlapped louver.

It is an object of the present invention to provide a simple mechanism by means of which oppositely rotating overlapping louvers will be so moved from closed position that the overlapping louver will lead the overlapped louver.

A further object is to provide such a mechanism that will additionally move all the louvers into parallel relation at full open damper position.

Other objects will be apparent from the drawing, specication, and claims.

In the drawing: v

Figure 1 shows a damper incorporating the invention in closed position. y

Figure 2 shows the same damper in full open position.

The damper shown in Figures 1 and 2 comprises a frame 6 which is of the conventional type and generally rectangular in form. Shafts 8, II),` I2, and I4 are journalled in the damper frame and are secured to the louvers 9, I I, I3, and I5, respectively. A rod I8 is pivoted to the louvers 9 and I3 and cause these two louvers to remain parallel. Likewise a rod is pivoted to louvers I I and I5to cause these louvers to move together. Thus it will be seen that louvers 9 and I3 remain parallel and louvers II and I5remain parallel. Angle brackets 23 are suitably secured to the top and bottom edges of the frame and serve as seals between louvers 9 and I5 and the frame 6 when the louvers are in closed position.

In order that alternate damper blades may be caused to move in reverse angular directions during both opening and closing movements of the damper, a mechanism is utilized which will now be described. Suitably pivoted at 24 in the frame 6 between the pivots 8 and IU for the louvers 9 and II is a bellcrank member 25. The louver 9 is provided with a bracket 26 between the pivot 8 and lower edge of the louver while the louver II is provided with a bracket 28 at a point below its pivot IIJ. A link 30 is attached tolouver 9 at the bracket 26 and is attached to the bell crank member 25 at a pivot 3|. The lower side of bell crank member 25 is attached at 33 to a link 35 which is connected to the bracket 28 of louver I I.

As shown in Figure 1 of the drawing the louver II is shaped at itsupper edge to overlap the louver 9 and to form a suitable seal therewith when in the closed position. Likewise the louver I3 overlaps the louver I I and the louver I5 overlaps the louver I3. It will be understood that when the damper is opened from the position shown in Figure 1, the louvers 9 and I3 will move in a clockwise direction while the louvers II and I5 move in a counter-clockwise direction. It will also be apparent that the louvers Il and I5 must move a greater distance initially from closed position than the louvers 9 and I3 in order that the adjacent edges may disengage as the damper opens. The links 3B and 35 together with the bell crank member 25 are so arranged that this may be accomplished. The instantaneous speeds of the louvers as they start to move from closed position will depend on the ratios between the perpendicular distances from the associated links 3U and 35 to the centers of the damper pivots and to the center of the bell crank pivot. As seen in Figure 1 the perpendicular distance from the louver pivot 8 to the projection of a line connecting the pivots 26 and 3| of the link 36 Vis desig- -nated as a, while the perpendicular distance from the center line of the link 35 to the pivot I0 of louver II is designated as a. The perpendicular distance from the center line of link 30 to the pivot 2d of the bell crank member 25 is indicated as b while the perpendicular distance from the projection of the center line oi' the link 35 to the pivot 24 for the bell crank member 25 is designated as b. The relation between the initial angular speeds of the louvers 9 and II as they move from the position shown in Figure l may therefore be designated as In the present showing, the distances a and a `have been made equal and therefore the ratio of initial speeds of damper blades 9 and II may be givenas'f y l Speed@ Speed Xg It will be seen therefore that since the perpendicular distance b' between the center line of the link 35 and the Pivot for the bell crank member 25 is greater than the perpendicular distance b between center line of the link 30 and the pivot 24 for the bell crank member 25, the louver II will lead louver 9 in initial opening movement and therefore their overlapping edges will clear. The

relation of the parts is also such that the louvers will be parallel in full open position of the damper as shown in Figure 2. Since alternate louvers of the damper as a whole are connected to louvers 9 and Il to move therewith all of the louvers will operate similarly to louvers v9 y and Il.

It will be understood that any suitable damper motor may be connected to the dampermechanism in the usual manner so that it may be automatically controlled.

It will therefore be seen that I have provided a simple mechanism for operating a damper in which alternate louvers overlap and are so con-L nected as to move in opposite angular directions.

I claim as my invention:

l. In a damper mechanism in which alternate louvers are adapted to rotate in relatively opposite angular directions, in combination, a frame, a iirst louver pivoted in said frame, a second louver an edge of which overlaps said first louver when the damper is in closed position also pivoted in said frame, a member pivoted in said frame between the pivots for said first and second louvers, the pivot for said member being parallel to. the pivots for said louvers, a rst link pivoted to said first louver at a point between the pivots for said louver and said member and to said member, a second link pivoted to said second louver on the side of the louver pivot away from the pivot for said member andv to saidmember, the proportions of the parts being such that in closed damper position the perpendicular distance from said second link to the pivot for said member is greater than the perpendicular distance from said first link to the pivot for said member. i

2. In a damper mechanism in which alternate louvers are adapted to rotate in relatively opposite angular directions, in combination, a frame, a rst louver pivoted in said frame, a second louver an edge of which overlaps said rst louver when the damper is in closed position also pivoted in said frame, a member pivoted in said frame between the pivots for said rst .and second louvers, the pivot for said member being parallel to the pivots for said louvers, a first link pivoted to said first louver at a point between the pivots vfor said louver and said member and to said member, a second link pivoted to said second louver on the side of the louver pivot away from the pivot for said member and to saidl member at such a point that at closed damper position the perpendicular distance from said second link to the pivot for said member is greater than the perpendicular distance from said first link to the pivot for said member.

3. In a damper mechanism in which alternate louvers are adapted to rotate in relatively opposite angular directions, in combination, a frame, a first louver pivoted in said frame, a second louver an edge of which overlaps said first louver when the damper is in closed position also pivoted in said frame, a bell-crank pivoted in said frame between the pivots for said louvers, the pivot for said bell-crank being parallel to the pivots for said louvers, a first link pivoted to said rst louver at a point between the pivots for said louver and saidbell-crank and to one arm of said bell-crank, a second link pivoted to said second louver on the side of the louver pivot away from the pivot for said bell-crank and to the other arm of said bell-crank at such ay point that at closed damper position the perpendicular distance from said second link to the pivot for said bell-crank is greater than the perpendicular distance from said iirst link to the pivot for said bell-crank.

4. In a damper mechanism in which alternate louvers are adapted to rotate in relatively opposite angular directions, in combination, a frame, a rst louver pivoted in said frame, a second louver an edge of which overlaps said rst louver when the damper is in closed position also pivoted in said frame, a member pivoted in said frame between the pivots for said rst and secondlouvers, the pivot forsaid member being parallel to the pivots for said louvers and substantially in the plane of the pivots for said louvers, a first link pivoted to said first louver at a point between the pivots for said louver and said member and to said member, a second link pivoted to said second louver on the side of the louver pivot away from the pivot for said member and to said member, the proportions of the parts being such that in closed damper position the perpendicular distance from said second link to the pivot for said member is greater than the perpendicular distance from said first link to the pivot for said member.

5. In a damper mechanism in which alternate louvers are adapted to rotate inl relatively opposite angular directions, in combination, a frame, a rst louver pivoted to said frame, a second louver also pivoted to said frame, an edge of said second louver overlapping an edge of said first louver when the damper is in a closed position, and leading said edgeof said rst louver in an initial opening movement, a member pivoted to said frame between the pivots for said louvers on an axis parallel to the axis of the pivots of said louvers, a first link pivoted to said rst louver on the side of the pivot of said first louver toward the pivot of said second louver, and to said member, a second link pivoted to said second louver on the side of the pivot of said second louver away from the pivot of said first louver, and to said member, the ratio of the perpendicular distance between said second link and the axis of said member to the perpendicular distance between said second link and the axis of said second louver being greater than the ratio of the perpendicular distance between said rst link and the axis of said member to the perpendicular distance between said first link and the axis of said' rst louver, when the damper is in closed .position JOHN L. HARRIS. 

